Satellite based communication systems provide an outstanding solution for the delivery of video to the consumer. However, to remain competitive with alternative delivery methods, such as cable and digital subscriber line, the satellite systems must provide a greater variety and quantity of content. Additionally, the introduction and migration to high definition television consumes larger amounts of the available spectrum. Thus, there is a continuously increasing requirement for greater bandwidth in satellite systems.
Initially, direct broadcast satellite systems operated in the Ku band, and received signals from a single satellite in geosynchronous orbit with a reflector less than one half meter in diameter. Increasing the capacity of such systems was achieved with multiple beams receiving signals from two or three satellites in geosynchronous orbits with 9 degree spacing. The reflector size was only slightly increased to compensate for the loss in gain on the offset beams.
To further increase capacity of such systems it is necessary to make use of satellites operating at Ka band with 2 degree orbital spacing. The antennas must be capable of receiving multiple beams in multiple bands while remaining less than 1 meter in diameter. However, the narrow beam angle of the ka band satellites forces the antenna feeds to be separated from each other by a distance that is proportional to the tangent of the beam angle and the reflector size. As a consequence, the antenna must be much greater than one meter in diameter to allow the feeds to be properly spaced such that the resulting beams are separated by two-degree angles. Large antennas are acceptable for some commercial operations; however they are unacceptable for consumer applications (e.g., where home owners associations limit the antenna dimensions to less than one meter).
It would be useful to be able to address the above deficiencies and to provide a small, multi-beam, multi-band reflector antenna with high efficiency and narrow beam separation.